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Discussion Starter · #1 ·
I have a 2015 Silverado with the 4.3L ecotec. I just took it in for a couple of recalls 2 weeks ago. 1 recall was a seatbelt issue and the other was an issue with the transmission potentially jumping out of 4 wheel drive in cold weather. To fix this problem the dealership had to "reprogram the computer". Previous to this recall I was getting 23-26 MPG. Now I am getting 19-21 MPG. Anyone else experiencing this after the recall?
 

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The above post is correct if the battery was disconnected or they (which I am sure they did) did a new flash of the ECU. Can take up to 100 miles of driving to adjust again, but be aware that some flash revisions will reduce fuel economy as they are working to reduce the intake valve coking issues. Anytime fuel trims are reset, it takes a bit for the ECU to adapt.
 

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I've had both recalls done. It did not affect my milage. However, since the end of October, my MPG has dropped about 20%. Partially because of my new tires, partially because of winter gas. I had a similar drop last year when winter gas started.
 

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Definitely winter blend and of course cold start enrichment, etc. and IAT tamp sensor all figure in. I forget being in FL that it still gets winter up North! Also, the more ethanol content, the worse the fuel economy as more ethanol has to be burned to achieve proper A/F ratio.
 

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Discussion Starter · #9 ·
Actually it was closer to a month ago now. I am basing my statement on average MPG reading on display. I know its a small sample size but I am definitely getting worse mileage. My driving habits, distances and area don't change much at all. The winter blend makes sense. I saw a similar drop in MPG last year around this time although not nearly as pronounced as it is this year. Thanks for all the replies and info. I feel a bit better now knowing that there are other factors this time year that are likely contributing to the drop in mileage.
 
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